(a) Field of the Invention
The invention relates to a matrix socket, and more particularly, to a matrix socket having a high terminal density, and is used for testing whether an integrated circuit achieves expected specifications.
(b) Description of the Prior Art
A desirable testing socket for integrated circuits must at least have the following characteristics:    1. keeping terminals of an integrated circuit undamaged; or else, an originally qualified integrated circuit may become an unqualified product due to terminal damages caused during testing process thereof; and    2. being electrically connected with all terminals in an integrated circuit; in an integrated circuit, quantity of terminals varies from as few as tens to as many as hundreds, and therefore it is essential that a testing socket be electrically connected with all the terminals in the integrated circuit to completely perform testing of the integrated circuit.
For that conventional terminals in an integrated circuit are made of metal materials, these integrated circuit terminals have excellent mechanical strength, and a testing socket for integrated circuits can thus be electrically connected with the integrated circuit terminals directly by clamping means. Such type of integrated circuit terminals made of metal materials is generally electrically connected with circuits in electronic devices by surface mounting technology (SMT type) or through hole (DIP type).
Owing to increase in terminal densities of conventional integrated circuits is the latest trend, industrial mass production of circuits at circuit boards in integrated circuits using the conventional SMT and DIP is made more and more difficult. Hence, metal terminals of integrated circuits are gradually replaced by solder balls. However, testing complications of packaged and assembled integrated circuits having solder ball terminals are caused as a result.
Surfaces of solder ball terminals have extremely low mechanical strength, and are also soft with high plasticity. Therefore, when using a testing socket for testing an integrated circuit, with solder ball terminals the solder balls are highly liable to deformation from excessive clamping forces or may even disengage from the integrated circuit. Prior techniques disclosed in the U.S. Pat. Nos. 5,498,970, 6,149,449 and 6,280,219 are not exempt from the above shortcoming.
Referring to the U.S. Pat. No. 5,247,250, wherein terminals of a testing socket disclosed come into contact with lower surfaces of solder balls, the terminals are instead easily shorted and the structure is hardly reliable.
To overcome the aforesaid drawbacks, the invention provides a matrix socket serving as not only an integrated circuit testing socket but also a common land grid array (LGA) socket.